Visual Basic

Me.Close()

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    Me.Close()
    form1.textbox1.focus ' <-- The code in question
End Sub

void Main()
{
    Application.Run(new Form1());
}

class Form1 : Form
{
    public Form1()
    {
        var btn = new Button();
        btn.Text = "Open Form2";
        btn.Click += btn_Click;
        Controls.Add(btn);
    }
    
    private void btn_Click(object sender, EventArgs e)
    {
        var form = new Form2();
        form.Show();
    }
}

class Form2 : Form
{
    public Form2()
    {
        var btn = new Button();
        btn.Text = "Close me";
        btn.Click += btn_Click;
        Controls.Add(btn);
    }
    
    private void btn_Click(object sender, EventArgs e)
    {
        Close();
        Console.WriteLine("Closed");
        MessageBox.Show("Closed");
    }
}

From MSDN[^]:

The CurrentChanged event is raised whenever the Current property changes for any of the following reasons:

1. The current position of the List changes.
   
2. The DataSource or DataMember properties change.
   
3. The membership of the underlying List changes, which causes Position to refer to a different item. Examples include adding or deleting an item before the current item, deleting or moving the current item itself, or moving an item to the current position.
   
4. The underlying list is refreshed by a new sorting or filtering operation.

Bastard Programmer from Hell
If you can't read my code, try converting it here[^]

System.Math.Max(System.Threading.Interlocked.Increment(i), i - 1)

System.Math.Max(System.Threading.Interlocked.Decrement(n), n + 1)

MyobjBindingSource.DataSource = (From t In context.myobjs Where t.art = art1
                                     Select t).ToList

dim context as new myEntities